protected void _handleMergeRequest(
Address sender, MergeId merge_id, Collection<? extends Address> mbrs) throws Exception {
boolean success = matchMergeId(merge_id) || setMergeId(null, merge_id);
if (!success)
throw new Exception(
"merge " + this.merge_id + " is already in progress, received merge-id=" + merge_id);
/* Clears the view handler queue and discards all JOIN/LEAVE/MERGE requests until after the MERGE */
// gms.getViewHandler().suspend();
if (log.isTraceEnabled())
log.trace(
gms.local_addr
+ ": got merge request from "
+ sender
+ ", merge_id="
+ merge_id
+ ", mbrs="
+ mbrs);
// merge the membership of the current view with mbrs
List<Address> members = new LinkedList<Address>();
if (mbrs
!= null) { // didn't use a set because we didn't want to change the membership order at this
// time (although not incorrect)
for (Address mbr : mbrs) {
if (!members.contains(mbr)) members.add(mbr);
}
}
ViewId tmp_vid = gms.getViewId();
if (tmp_vid != null) tmp_vid = tmp_vid.copy();
if (tmp_vid == null) throw new Exception("view ID is null; cannot return merge response");
View view = new View(tmp_vid, new ArrayList<Address>(members));
// [JGRP-524] - FLUSH and merge: flush doesn't wrap entire merge process
// [JGRP-770] - Concurrent startup of many channels doesn't stabilize
// [JGRP-700] - FLUSH: flushing should span merge
/*if flush is in stack, let this coordinator flush its cluster island */
if (gms.flushProtocolInStack && !gms.startFlush(view)) throw new Exception("flush failed");
// we still need to fetch digests from all members, and not just return our own digest
// (https://issues.jboss.org/browse/JGRP-948)
Digest digest = fetchDigestsFromAllMembersInSubPartition(members, merge_id);
if (digest == null || digest.size() == 0)
throw new Exception(
"failed fetching digests from subpartition members; dropping merge response");
sendMergeResponse(sender, view, digest, merge_id);
}
/**
* Merge all MergeData. All MergeData elements should be disjunct (both views and digests).
* However, this method is prepared to resolve duplicate entries (for the same member).
* Resolution strategy for views is to merge only 1 of the duplicate members. Resolution
* strategy for digests is to take the higher seqnos for duplicate digests.
*
* <p>After merging all members into a Membership and subsequent sorting, the first member of
* the sorted membership will be the new coordinator. This method has a lock on merge_rsps.
*
* @param merge_rsps A list of MergeData items. Elements with merge_rejected=true were removed
* before. Is guaranteed not to be null and to contain at least 1 member.
*/
private MergeData consolidateMergeData(List<MergeData> merge_rsps) {
long logical_time = 0; // for new_vid
List<View> subgroups =
new ArrayList<View>(11); // contains a list of Views, each View is a subgroup
Collection<Collection<Address>> sub_mbrships = new ArrayList<Collection<Address>>();
for (MergeData tmp_data : merge_rsps) {
View tmp_view = tmp_data.getView();
if (tmp_view != null) {
ViewId tmp_vid = tmp_view.getVid();
if (tmp_vid != null) {
// compute the new view id (max of all vids +1)
logical_time = Math.max(logical_time, tmp_vid.getId());
}
// merge all membership lists into one (prevent duplicates)
sub_mbrships.add(new ArrayList<Address>(tmp_view.getMembers()));
subgroups.add(tmp_view.copy());
}
}
// determine the new digest
Digest new_digest = consolidateDigests(merge_rsps, merge_rsps.size());
if (new_digest == null) return null;
// remove all members from the new member list that are not in the digest
Collection<Address> digest_mbrs = new_digest.getMembers();
for (Collection<Address> coll : sub_mbrships) coll.retainAll(digest_mbrs);
List<Address> merged_mbrs = gms.computeNewMembership(sub_mbrships);
// the new coordinator is the first member of the consolidated & sorted membership list
Address new_coord = merged_mbrs.isEmpty() ? null : merged_mbrs.get(0);
if (new_coord == null) return null;
// should be the highest view ID seen up to now plus 1
ViewId new_vid = new ViewId(new_coord, logical_time + 1);
// determine the new view
MergeView new_view = new MergeView(new_vid, merged_mbrs, subgroups);
if (log.isTraceEnabled())
log.trace(
gms.local_addr
+ ": consolidated view="
+ new_view
+ "\nconsolidated digest="
+ new_digest);
return new MergeData(gms.local_addr, new_view, new_digest);
}
public int size() {
int retval = Global.BYTE_SIZE * 2; // type + merge_rejected
retval += Global.BYTE_SIZE; // presence view
retval += Global.BYTE_SIZE; // MergeView or View
if (view != null) retval += view.serializedSize();
retval += Util.size(mbr);
retval += Util.size(mbrs);
retval += Global.BYTE_SIZE; // presence of join_rsp
if (join_rsp != null) retval += join_rsp.serializedSize();
retval += Global.BYTE_SIZE; // presence for my_digest
if (my_digest != null) retval += my_digest.serializedSize();
retval += Global.BYTE_SIZE; // presence for merge_id
if (merge_id != null) retval += merge_id.size();
retval += Global.BYTE_SIZE; // boolean useFlushIfPresent
return retval;
}
/**
* Get the view and digest and send back both (MergeData) in the form of a MERGE_RSP to the
* sender. If a merge is already in progress, send back a MergeData with the merge_rejected field
* set to true.
*
* @param sender The address of the merge leader
* @param merge_id The merge ID
* @param mbrs The set of members from which we expect responses
*/
public void handleMergeRequest(
Address sender, MergeId merge_id, Collection<? extends Address> mbrs) {
boolean success = matchMergeId(merge_id) || setMergeId(null, merge_id);
if (!success) {
if (log.isWarnEnabled()) log.warn(gms.local_addr + ": merge is already in progress");
sendMergeRejectedResponse(sender, merge_id);
return;
}
/* Clears the view handler queue and discards all JOIN/LEAVE/MERGE requests until after the MERGE */
gms.getViewHandler().suspend(merge_id);
if (log.isDebugEnabled())
log.debug(
gms.local_addr
+ ": got merge request from "
+ sender
+ ", merge_id="
+ merge_id
+ ", mbrs="
+ mbrs);
// merge the membership of the current view with mbrs
List<Address> members = new LinkedList<Address>();
if (mbrs
!= null) { // didn't use a set because we didn't want to change the membership order at this
// time (although not incorrect)
for (Address mbr : mbrs) {
if (!members.contains(mbr)) members.add(mbr);
}
}
ViewId tmp_vid = gms.view_id != null ? gms.view_id.copy() : null;
if (tmp_vid == null) {
log.warn("view ID is null; cannot return merge response");
sendMergeRejectedResponse(sender, merge_id);
return;
}
View view = new View(tmp_vid, new Vector<Address>(members));
// [JGRP-524] - FLUSH and merge: flush doesn't wrap entire merge process
// [JGRP-770] - Concurrent startup of many channels doesn't stabilize
// [JGRP-700] - FLUSH: flushing should span merge
/*if flush is in stack, let this coordinator flush its cluster island */
boolean successfulFlush = gms.startFlush(view);
if (!successfulFlush) {
sendMergeRejectedResponse(sender, merge_id);
if (log.isWarnEnabled())
log.warn(
gms.local_addr
+ ": flush failed; sending merge rejected message to "
+ sender
+ ", merge_id="
+ merge_id);
cancelMerge(merge_id);
return;
}
Digest digest = fetchDigestsFromAllMembersInSubPartition(members);
if (digest.size() == 0) {
log.error("failed fetching digests from subpartition members; dropping merge response");
return;
}
sendMergeResponse(sender, view, digest, merge_id);
}